Nervous System

Major Function To control all activities of the body

Diversity of Nervous Systems Simple, slow moving animals like hydra have neurons arranged in a network of bipolar neurons called a nerve net.

Basic Tasks of the Nervous System Sensory Input: Monitor both external and internal environments. Integration: Process the information and often integrate it with stored information. Motor output: If necessary, signal effector organs to make an appropriate response.

The Central Nervous System The CNS or central nervous system consists of the brain and spinal cord The Brain- The control Center, Coordinates all body functions    Spinal Cord – transmits messages between the brain and the rest of the body.

Peripheral Nervous System Consists of nerves that relay messages between the CNS and the rest of your body

The “funny bone” is on the elbow. You have a nerve along your whole arm. "Funny Bone" The “funny bone” is the only place on the arm where the nerve is not protected. The “funny bone” is on the elbow.

Neurons Nerve cell that transports signals

Anatomy of a Neuron Cell body: functional portion Dendrites: short extensions that receive signals Axon: long extension that transmits impulses away

Neuron

Myelinated Neurons Many vertebrate peripheral neurons have an insulating sheath around the axon called myelin which is formed by Schwann cells. Myelin sheathing allows these neurons to conduct nerve impulses faster than in non-myelinated neurons.

These nerves transmit information relating to smell, taste, sight, sound, touch, and balance back to the brain

The nerves in the human hand The Nervous System The nerves in the human hand 1. Motor nerve fibers – allow movement 2. Sensory nerve fibers allow you to feel…

The Brain Brain is the control center of the Nervous System

The Three Parts of the Brain * The Brain has three main parts… 1. The Cerebrum 2. The Cerebellum 3. The Brain Stem

* The Cerebrum is the largest part of the brain. 1. The cerebrum controls your thinking. 2. The cerebrum controls your memory. 3. The cerebrum controls your speaking. 4. The cerebrum controls your movement and identifies the information gathered by your sense organs.

The Brain Cerebrum- Largest part of the brain; made of several parts.

Cerebrum Parts Include… Hypothalamus-regulates temperature of blood, appetite and emotions. Cerebral Cortex- Interprets signals from the eyes, ears, hands, and nose; controls muscle movement, and is responsible for intelligence.

* The cerebellum is below and to the back of the cerebrum. 1. The cerebellum controls you balance. 2. The cerebellum controls your posture.

The Brain Stem * The Brain Stem connects the brain to the spinal cord. * The nerves in the brain stem control your heartbeat, breathing, and blood pressure.

The Brain Brain Stem- Controls breathing and heart beat. Cerebellum- controls sense of balance and coordinates the actions of muscles.

Nervous System Disorders Multiple Sclerosis- Disorder in which the myelin surrounding neurons deteriorate making it hard for signals to travel from one neuron to the next. Symptoms include: loss of motor skills, blindness, numbness, and loss of balance. Caused by white blood cells attacking the nervous system

Nervous System Disorders Alzheimer Disease- Degeneration of nervous tissue that can cause memory loss, loss of verbal communication, and motor skills.

Nervous System Disorders Huntington’s Disease- genetic disorder that affects muscle coordination and causes involuntary twitching. Tourette’s Syndrome- irregular movements of the head, neck, or shoulders.  They also may be more complex motor behaviors such as snorting, sniffing, and involuntary vocalization

Did you Know? There are more nerve cells in the human brain than there are stars in the Milky Way. If we lined up all the neurons in our body it would be around 600 miles long. There are 100 billion neurons in your brain alone. A newborn baby's brain grows almost 3 times during the course of its first year.

Did you know? The left side of human brain controls the right side of the body and the right side of the brain controls the left side of the body. Only four percent of the brain's cells work while the remaining cells are kept in reserve. Neurons are the largest cells in the human body. (They can be up to 3 feet long) The Nervous System can transmit impulses as fast as 100 meters per second.